1. Field of the Invention
The present invention relates to a ski with a core located between a top strap and a bottom strap. An intermediate ply is located over the top strap. Either the core or the intermediate ply, or both, vary in thickness or width, or both, over the length of the ski, resulting in a profiled top. A reinforcement or damping element or both can be formed from the intermediate ply.
2. The Prior Art
A ski is disclosed in Austrian Patent AT-PS 380,172, which describes a plastic foamed core in between a top strap and a bottom strap forming sheet-like components. The top strap is profiled by supporting the top strap in a mold and by injecting the plastic foam under pressure into the core part. This process requires a very large number of complicated molding dies, as a different mold is required for each different ski length.
In another known ski, pursuant to German Patent DE-OS 39 37 617, a strip-shaped plastic band is laid into a U-shaped plastic profile which is connected to the core. With this structure, however, longitudinally extending cracks may form along the top into which snow and ice can penetrate.
Another ski is disclosed in U.S Pat. No. 4,679,813, which describes the use of a torsion rod. This rod is attached to the top surface of the ski, in order to resist twisting. However, the top surface of the ski is disrupted by the torsion rod, and spots form in which snow and ice can become lodged. This rod may also undesirably stiffen the ski under certain conditions.
Yet another known ski disclosed in the inventor's Austrian Patent AT-PS 347 831 has a top strap and a bottom strap, arranged around a core. The core varies in thickness over its length. The core includes at least one intermediate strap, extending from the tip of the ski to approximately the end of the ski. This intermediate layer varies in distance from the top strap, while maintaining a constant distance from the bottom strap. This makes it possible to vary the thickness of the ski over its entire length. The ski can thus correspondingly counteract the different stresses and levels of bending momentum which occur. Additionally, this provides sufficient pretension against bending of the ski in the direction of the running surface.
Another ski disclosed in Austrian Patent AT-PS 386,126 describes a ski structured as a sandwich element which is formed with a core and a top and bottom strap. Between the binding region and the two ends of the ski, roof-shaped raised projections are arranged over the surface of the ski, with additional core components placed therein. These roof-shaped projections, however, only affect the aesthetics of the ski. The configuration of the core material, and the different lengths of the skis, result in unpredictable properties of the ski.